FINAL API 653 Inspection 

Report

PRL 03-12: Internal Inspection of Tank 6, Red 

Hill

FISC Pearl Harbor, 

Hawaii

Prepare

d for:

Air Force Center for Environmental Excellence Worldwide 

Environmental Restoration and Construction Contract 

Contract Number: FA8903-04-D-8681

Task Order: 

0176

January 

2007
Weston Solutions, Inc.

841 Bishop Street 

Suite 2301 

Honolulu, Hawaii 96813 

808-275-2900 ● Fax 808-585-7378 

29 January 2007 

Ms. Kim Chang 

AFCEE IWE 

25 E. Street, Suite E-317 

Hickam AFB, HI 96853 

RE: Submittal of Final API 653 Inspection 

Report Internal Inspection of Tank 6 (PRL 03-

12) FISC Pearl Harbor, Hawaii 

FA8903-04-D-8681,Task Order Number 0176 

(CDRL A001A and B010) 

Dear Ms. Chang: 

Please find the enclosed Final API 653 Inspection Report for the Internal Inspection of Tank 6 project. 

Hard and electronic copies of this submittal have also been forwarded to the recipients listed below. 

Please call me at (808) 275-2948, or email me at d.desario@WestonSolutions.com with any questions 

or comments. 

Sincerely, 

Weston Solutions, Inc. 

Daniel F. DeSario JenniferJohnson, PE 

Project Manager Fuel System Services, Technical Manager 

API 653 Inspector – No. 24570 API 653 Inspector – No. 24694 

API 570 Inspector – No. 27637 API 570 Inspector – No. 25784 

Enclosures 

cc: AFCEE – MSCD (w/o att.) 

FISC, Pearl Harbor, Terry Strack (2 copies) 

Lisa Blandford 

Program File 

Project File 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6, Red Hill

FISC Pearl Harbor, Hawaii

Prepared for

Air Force Center for Environmental Excellence

Worldwide Environmental Restoration and Construction Contract

Prepared By

Weston Solutions, Inc.

841 Bishop Street, Suite 2301

Honolulu, HI 96816

Contract No. FA8903-04-D-8681

Task Order: 0176

January 2007

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page i

TABLE OF CONTENTS

Section Page 

1.0 INTRODUCTION.............................................................................................................. 1-1

2.0 PRELIMINARY API 653 INSPECTION ........................................................................ 2-1

2.1 LFET SHELL AND BFET WELD SCANNING AND UT MEASUREMENTS .... 2-1 

2.2 API 653 EVALUATION ........................................................................................... 2-1 

2.3 FINDINGS/RECOMMENDATIONS ....................................................................... 2-5 

2.4 CONCLUSIONS........................................................................................................ 2-7 

LIST OF TABLES
Table Title Page 

Table 2-1 Patch Plate and Weld Repair Summary............................................................... 2-8 

LIST OF APPENDICES

Appendix A Low Frequency Electromagnetic Technique Inspection 

Appendix B Photographic Documentation 

Appendix C Historical Information 

Appendix D Repair Sketches 

Appendix E Strapping Table 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page ii

LIST OF ACRONYMS

ACCP ASNT Central Certification Program 

AFCEE Air Force Center for Environmental Excellence 

API American Petroleum Institute 

ASME American Society of Mechanical Engineers 

ASNT American Society for Non-Destructive Testing 

ASTM American Society for Testing and Materials 

BFET Balance Field Electromagnetic Technique 

BPVC Boiler and Pressure Vessel Code 

DESC Defense Energy Support Center 

FISC Fleet and Industrial Supply Center 

LFET Low Frequency Electromagnetic Technique 

MT Magnetic Particle (testing) 

NDE Non-Destructive Examination 

PT Liquid Penetrant (testing) 

TO Task Order 

UT Ultrasonic Thickness (testing) 

VB Vacuum Box (testing) 

VT Visual Inspection 

WPS Welding Procedure Specifications 
Executive Summary

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page iii

Under contract agreement (Contract No. FA8903-04-D-8681/0176) with the Air Force Center for 

Environmental Excellence (AFCEE), Weston Solutions, Inc. has prepared this Final API 653 

Inspection Report for the Defense Energy Support Center’s (DESC) Project PRL 03-12, Internal 

Inspection of Tank 6 in Red Hill. The facility is part of the Fleet Industrial Supply Center (FISC) 

Pearl Harbor, Hawaii. 

Tank 6 was built in 1942 (completed 1943). Its nominal capacity is 302,000 barrels. The tank, 

like the others in Red Hill, is an underground concrete tank with a steel liner. The configuration 

is a vertical cylinder measuring 100 feet in diameter and 250 feet in height. The tank is domed 

on the lower and upper ends. 

This inspection task consisted of an out-of-service, modified API 653 inspection of Tank 6 in 

Red Hill. The work included nondestructive examination (NDE) and evaluation of data for the 

upper dome (courses A, B, C, D, E, and F), the extension, the area under the catwalk, the barrel, 

the lower dome (courses 1, 2, 3, and 4), and the bottom. Eighty percent of the entire tank area 

underwent NDE, including 100% of the barrel and extension. 

Hand held electromagnetic scanners were used for NDE of the steel liner plates of the tank. 

When defects/flaws were found, then ultrasonic thickness (UT) measurements were taken to 

establish actual thicknesses in these areas. Welds were inspected with eddy current probes. 

When defects/flaws were found, then shear wave (angle beam) ultrasonic testing was performed 

to establish the remaining thickness at the weld flaw locations. 

Based on the information gathered during the inspection of Tank Nos. 15 and 16 the corrosion 

rate has been calculated to be 0.0045 inches per year. Applying this repair threshold to the 684 

defects/flaws detected in Tank 6 results in a requirement / recommendation that approximately 

476 defects/flaws be repaired for a twenty year re-inspection cycle. An abbreviated summary of 

the required/recommended repairs of the tank shell/liner is as follows: 

Weld Repairs – 268 Patch Plates - 193 (200 flaws) Coating Repair Only - 8 

Upon successful completion of the recommended repairs, the next internal and UT inspection of 

Tank 6 should be performed no later than 3 May 2026. The overall effectiveness of the Dunkin 

& Bush, Inc. repairs appeared to have satisfactorily addressed flaws detected in Tank 6. Repairs 

were performed in accordance with the recommendations. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page iv

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Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 1-1
1.0 INTRODUCTION

Under contract agreement (Contract No. FA8903-04-D-8681/0176) with the Air Force Center for 

Environmental Excellence (AFCEE), Weston Solutions, Inc. has prepared this Final API 653 

Inspection Report for the Defense Energy Support Center’s (DESC) Project PRL 03-12, Internal 

Inspection of Tank 6 in Red Hill. The facility is part of the Fleet Industrial Supply Center (FISC) 

Pearl Harbor. Weston Solutions, Inc. is/was under contract to perform a modified API 653 

Inspection, develop new calibration tables, and install a datum plate. 

The Red Hill Fuel Facility is located on the island of Oahu, Hawaii and is used to store fuel in 

support of military operations on Oahu, in the mid-Pacific area, and other areas as required. The 

site is located within the ridgeline between South Halawa Valley and Moanalua Valley. The site 

is built into the ridgeline, encasing a network of 20 subterranean tanks. Access to the facility is 

through secure Navy property, and access to the fuel tanks and piping is by elevator and the 

upper and lower tunnels. 

Tank 6 was built in 1942 (completed in 1943). Its nominal capacity is 302,000 barrels (listed as 

302,286 barrels). The tank, like other tanks in Red Hill, is a concrete tank with a steel liner. The 

configuration is a vertical cylinder measuring 100 feet in diameter and 250 feet in height. The 

tank is domed on the lower and upper ends. The primary access point to the tank is from the 

upper tunnel which is at the 200 foot level of the tank. The tank has a center tower extending 

from the top to the bottom that is connected to the access point by a catwalk. Cleaning, 

inspection, and repair of the shell liner (including the domes) are made possible by boom 

suspended scaffolding that is operated from the center tower and the suspended baskets. 

This API 653 Inspection Report outlines the inspection approach, the evaluation methodology, 

and the findings/recommendations. 

Inspection Approach

This inspection task consisted of an out-of-service modified API 653 inspection of Tank 6 in Red 

Hill. The work included evaluation of Courses A, B, C, D, E, and F of the upper dome, the 

extension, the area under the catwalk, 100% of the barrel, courses 1, 2, 3, and 4 the lower dome, 

and the bottom. 

Electromagnetic inspection/testing was followed by Ultrasonic Thickness (UT) measurement 

prove-ups. The electromagnetic inspections utilized hand scanners capable of low frequency 

electromagnetic technique (LFET) for the shell liner and balance field electromagnetic technique 

(BFET) on the welds. 

Hand held electromagnetic scanners were used to test the steel liner plates of the tank. When 

defects/flaws were found, then UT measurements were taken to establish actual thicknesses in 

these areas. Welds were inspected with BFET eddy current probes. When defects/flaws were 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 1-2

found, then shear wave ultrasonic testing was performed to establish the remaining thickness at 

the weld flaw locations. Furthermore, the cover plates covering the joints and backing bars 

throughout the extension and upper dome were UT measurement tested every foot. Existing 

patch plates located throughout the tank were UT measurement tested.
Evaluation Methodology

API 653 can be implemented when the tank design/construction is in accordance with API 650 

or API 12C and the tank is aboveground. Tank 16 is an underground concrete tank with an 

internal steel liner. Due the design / construction of the tank all of the principles and checklists 

provided in API 653 cannot be used for this tank inspection. For example, the steel liner which 

is interlocked or embedded to the concrete acts as a barrier between the product and the concrete 

‘shell’. Since Tank 6 is not a free-standing aboveground storage tank, the API 653 calculations 

evaluating the minimum shell thickness is not applicable to evaluate the steel liner. However it 

is feasible to implement the API 653 calculations for minimum bottom plate thickness to 

evaluate the steel liner located throughout the barrel, expansion joint, extension, domes, and 

bottom. Therefore, for this inspection the applicable portions of API 653 have been utilized, 

resulting in a modified API 653 inspection. 

A review of available historical information was performed. Visual inspection/evaluation of 

existing conditions throughout the tank was also conducted. Inspection of the 32” inlet/outlet 

line and visual inspection of the tank bottom were also performed. 

Recommendations

The findings (defects/flaws) are listed in table format, depicted in photographs when applicable, 

and discussed as necessary. The recommendations are based on the evaluation of the data and 

the principles of API 653. In areas where the principles of API 653 do not apply, decisions were 

made based on sound engineering judgment. 

Recommendations of required repairs were submitted for government review and approval on 18 

May 2007. Dunkin & Busch performed the repairs. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 2-1

2.0 PRELIMINARY API 653 INSPECTION

2.1 LFET SHELL AND BFET WELD SCANNING AND UT MEASUREMENTS

The scanning and testing effort, beginning on March 27, 2006 and completing on May 2, 2006, 

consisted of scanning by TesTex, Inc. under contract to Weston Solutions, Inc. This scanning 

was performed on Courses A, B, C, D, E, F (upper dome), the extension, the area under the 

catwalk, 100% of the barrel, courses 1, 2, 3, and 4 of the lower dome, the bottom, and UT 

measurements on the 32” and 18” inlet/outlet lines. 

The scanning was performed using the TesTex developed TS-2000 NDT Multichannel System for 

plate scanning and the principles of the LFET. The Hawkeye Digital Inspection System was used 

for weld scanning. Shear wave ultrasonic thickness measurement equipment was used to further 

evaluate weld flaws. A total of 684 defects/flaws were located during this inspection/testing 

effort. 

The TesTex, Inc. report for the inspection/testing effort is provided in Appendix A. Photographs 

depicting conditions of certain features in the tank as well as the scanning task are provided in 

Appendix B. 
2.2 API 653 EVALUATION 

History

Tank 6 was built in 1942 (completed in 1943). Its nominal capacity is 302,000 barrels. The tank 

is a concrete tank with a steel liner. The configuration is a vertical cylinder measuring 100 feet 

in diameter and 250 feet in height (internal). The tank is domed on the lower and upper ends. 

The primary access point to the tank is from the upper tunnel which is at the 200 foot level of the 

tank. The nominal plate thickness is 1⁄4-inch throughout the upper dome, extension, barrel, and 

lower dome the nominal plate thickness on the bottom is 1⁄2-inch. The tank was coated in the 

early 1980s with a thin film polyurethane coating. 

The tank history information (Appendix C) indicates that the tank developed its first potential 

leak from a location on the collector ring. This potential leak was discovered and repaired on 

July 23, 1952. 

In 1963 suspect leaks in the telltale system were addressed by smoke tracer testing, pressure 

testing, and physical repairs. The telltale systems in the Red Hill tanks were actually 

problematic and created releases from the tank into the telltale system. The telltale system in 

Tank 6 was removed and the openings created by the removal were closed with lap patch plates. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 2-2

The interior of the tank was coated during a contract repair cycle in 1981 and 1982. No specific 

details regarding other potential repairs performed at that time are available. 

Along with the patch plates used to close the telltale system, interspersed patch plates were also 

found adjacent to and on welds of the shell liner. These patch plates located near or on welds do 

not indicate backside corrosion so much as they were likely repairs to the welds themselves. 

There is no documented information that would indicate that back side corrosion has resulted in 

a through hole in the tank. However, there is a possibility that backside corrosion resulted in a 

through hole that was subsequently repaired during the 1998 repair cycle. 

Repair Threshold for Plate and Weld Flaws

While this inspection revealed no definitive evidence of a backside corrosion resulting in a 

through hole, as a conservative measure the corrosion rate/repair threshold that was used for 

Tanks 15 and 16 has been applied to this tank. This results in a calculated corrosion rate of 

0.0045 inches per year based on a suspected backside corrosion through hole in 1998 (0.25 in / 

(1998-1943)). This rate establishes a 20 year internal inspection interval resulting in a minimum 

remaining plate thickness of 0.1 inches with a repair threshold of 0.190 inches since an internal 

coating system is in-place to eliminate internal corrosion.

The following information was used to determine the corrosion rate and repair threshold: 

Nominal Shell (steel liner) Thickness 0.25 inches

Minimum Remaining Thickness at Or MRT 0.1 inches

In-service Interval of Operation Or 20 years
Year of Construction 1943 year

Year of Inspection (underside corrosion extends through full thickness) 1998 year 

Maximum Corrosion Rate (underside) UPr 0.0045 inches/year 

Minimum Remaining Thickness (after repairs) 0.190 inches 

Applying this repair threshold to the 684 defects/flaws detected, results in a requirement / 

recommendation that approximately 476 defects/flaws be repaired. Of the 476 flaws, 200 will 

require repair by the installation of 193 patch plates. Several patch plates will be used to repair 

multiple flaws. Another 268 flaws will require weld repair. The remaining eight flaws require 

coating repair only. An additional 57 flaws detected could not be tested by straight or angle 

beam UT to determine the remaining thickness due to their locations. These flaws should be 

tested by vacuum box. There are two locations that will require magnetic particle (MT) testing. 

The Patch Plate and Weld Repair Summary is provided as Table 2-1. Repair sketches are 

provided in Appendix D. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 2-3

32-inch Inlet/Outlet Line

The 32-inch line from the internal flange to the 20-inch flange in the lower tunnel was pressured 

tested by Dunkin & Bush, Inc. at 150 PSIG and pressure loss was observed. A leak was noted 

on the weld on the underside of the tunnel side flange. This leak requires repair and follow-up 

non-destructive examination (NDE). The evaluation of the tank also included observations of the 

internal portion of the 32-inch inlet/outlet line. The observation revealed that portions of the 

circumferential butt welds have incomplete penetration. The circumferential butt welds on the 

32-inch line that have incomplete penetration require repair (see repair sketches in Appendix D). 

There is an unused 3⁄4-inch pipe inside the 32-inch line. The 3⁄4-inch pipe and the internal 

supports should be removed and the internal opening should be seal welded. After all required 

repairs and NDE, the 32-line will need to be pressure tested again. The repairs were completed. 

18-inch Inlet/Outlet line

There is an 18-inch inlet/outlet line on the bottom of the tank. The line from the internal flange 

to the 12-inch flange in the lower tunnel was pressured tested by Dunkin & Bush, Inc. at 150 

PSIG for 4 hours and no pressure loss was observed. The supports and reinforcing plate are 

corroding, are undersized, and were constructed in a manner that produced angles that cannot be 

easily coated. The pipe supports and reinforcing pads (2 each) for the 18-inch line should be 

repaired by replacement. The repair was completed. 

Four 3⁄4-inch Sample Lines and 4-inch Slop (water draw-off) Line

The 4 x 3⁄4-inch sample lines were pressure tested at 150 PSIG for 4 hours and pressure loss was 

observed in one sample line. It is recommended that all four sample lines be replaced to 

complete this required repair (see repair drawing in Appendix D). The sample lines were 

replaced as recommended. The 4-inch slop line failed to maintain pressure during the pressure 

test and was repaired. 

Coating Evaluation
The coating throughout the lower dome will require repair. Isolated locations where the coating 

has failed in the upper dome will require repair. All patch plate and weld repair locations will 

require coating repair. Grout nozzles located in the extension and upper dome that are not 

scheduled for repair will require evaluation for possible coating repairs. 

Strapping and Installation of a Datum Plate

Weston Solutions, Inc. retained Gauge Point Calibration to develop calibrated capacity tables for 

the Tank (Appendix E). The total capacity was determined to be 301,491.58 barrels. WESTON 

retained Dunkin & Bush, Inc. to install a datum plate on the bottom beneath the mass tank gauge 

(MTG) probe. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 2-4

Repair Inspections

Weston Solutions, Inc. re-visited Tank 6 on several occasions to clarify repair recommendations 

and evaluate the repair process. The following summarizes the additional/follow-up inspections 

performed by Weston Solutions, Inc.: 

Flaw No. 30 

On June 27, 2006 Weston Solutions, Inc. re-visited Tank 6 to clarify the recommendation on 

how to repair Flaw No. 30. During the process of the repairs the welder had noted an eight inch 

crack running through the center of the weld. The repair was recommendation was modified to 

include the installation of a tombstone shaped patch plate after the recommended repair was 

completed. Repairs were completed in accordance with the recommendations. 

Flaw No. 547 

On August 23, 2006 Weston Solutions, Inc. re-visited Tank 6 to clarify the recommendation on 

how to repair Flaw No. 547. During the repair process it was noted that existing weld to new 

weld spacing would be better served by the use of a tombstone shaped patch plate. The 

recommendation was changed from an eight inch round patch plate to an eight tombstone patch 

plate. The repair was completed in accordance with the recommendations. 

Furthermore, during the Weston Solutions, Inc. re-visits to Tank 6, the Dunkin & Bush, Inc. 

repair efforts were qualitatively evaluated when required for clarification of recommendations. 

All repairs performed on the tank underwent non-destructive examination (NDE). If a repair 

failed the NDE, the repairs were reworked until it passed the NDE. Dunkin & Bush, Inc. 

reported that they maintained a log of all repairs made, NDE performed, and re-work required. 

Weston Solutions, Inc. visually inspected the repair work and found the workmanship to be of an 

acceptable quality (satisfactory). This is reasonable given the complexity of performing tank 

repairs in Red Hill, i.e. making repairs from suspended scaffolding. The overall difficulty of the 

task of completing the repairs does not lend itself to regularly achieving exceptional 

workmanship results. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176
Page 2-5

2.3 FINDINGS/RECOMMENDATIONS

1. Install 193 patch plates to repair 200 flaws as listed on Table 2-1 Patch Plate and Weld 

Repair Summary. The patch plates shall be ASTM A-36 carbon steel. Install patch plates 

with toe-to-toe weld spacing as indicated on repair sketches, noted on the summary table, and 

in accordance with the requirements of API 653 when the sketches and summary table are 

not specific. Patch plates shall be examined/tested by vacuum box, liquid penetrant, and 

visual methods in accordance with written procedures complying with ASME BPVC Section 

V, AWS, and/or API 650. 

2. Perform 268 weld repairs on weld flaws as listed in Table 2-1, Patch Plate and Weld 

Repair Summary. Weld repairs shall be examined by vacuum box, liquid penetrant, and 

visual methods. 

3. Perform eight additional coating repairs as listed in Table 2-1, Patch Plate and Weld Repair 

Summary. 

4. Perform vacuum box testing on 57 flaws as listed in Table 2-1, Patch Plate and Weld Repair 

Summary. 

5. Perform MT testing at two locations as listed in Table 2-1, Patch Plate and Weld Repair 

Summary. 

6. Repair by replacing the supports and reinforcing plates (2 each) for the 18-inch 

inlet/outlet line. Shop drawings are to be prepared, provided, and approved prior to the 

completion of the repair. Reinforcing plate welds shall be examined by vacuum box, liquid 

penetrant, and visual methods. 

7. Perform weld repair on approximately 40 feet of circumferential butt weld on the inside 

of the 32-inch inlet/outlet line to correct the lack of penetration condition. Repair the leak on 

the weld on the underside of the tunnel side flange per the repair sketch in Appendix D. The 

internal 3⁄4-inch pipe and the internal supports should be removed and the internal opening 

should be seal welded. After all required repairs and NDE the 32-line will need to be 

pressure tested again. The weld repairs shall be examined/tested by the liquid penetrant and 

visual methods. 

8. Repair the 3⁄4-inch sample line(s) per the repair drawing in Appendix D. 

9. The coating in the tank should be repaired in accordance with a NACE inspector’s or 

coating specialist’s recommendations (not necessarily re-coated entirely). A coating present 

on the interior surface allows for the exclusion of stock side corrosion rate when calculating 

an operational life for the tank. Patch plates, weld repairs, most of the lower dome, and 

portions of the upper dome will require coating repair. Grout nozzles located in the extension 

and upper dome that are not scheduled for repair will require evaluation for possible coating 

repairs. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 2-6
The repair contractor shall utilize Welding Procedure Specifications (WPS) proven by Procedure 

Qualification Records (PQR). Welders shall be certified in accordance with ASME Boiler and 

Pressure Vessel Code (BPVC) Section IX. 

In accordance with API 650 and ASME BPVC Section V non-destructive examination (NDE) 

technicians/examiners shall be certified per: (1) SNT-TC-1A, Personnel Qualification and 

Certification in Nondestructive Testing; or (2) ANSI/ASNT CP-189, ASNT Standard for 

Qualification and Certification of Nondestructive Testing Personnel; or (3) ACCP, ASNT 

Central Certification Program. 

Final API 653 Inspection Report

PRL 03-12: Internal Inspection of Tank 6

Red Hill, FISC Pearl Harbor

Contract No. FA8903-04-D-8681, TO 0176

Page 2-7

2.4 CONCLUSIONS

Upon successful completion of the recommended repairs, the next internal and UT inspection of 

Tank 6 should be performed no later than 3 May 2026. The overall effectiveness of the Dunkin 

& Bush, Inc. repairs appeared to have satisfactorily addressed flaws detected in Tank 6. Repairs 

were performed in accordance with the recommendations.